Dry skin, also known as xerosis or asteatosis, affects millions of Americans each year. Attempts to treat or prevent dry skin have led to the development of a large assortment of skin creams and lotions. All of these creams and lotions have been developed from either the point of view that applying an occlusive lipid such as petrolatum or mineral oil can retard moisture loss from the skin, or that the incorporation of water-soluble materials, such as free amino acids, organic acids, inorganic ions or urea, into the cream, ointment, gel or lotion can trap or retain water in the skin.
It has been demonstrated over the last few years that the stratum corneum of the skin contains certain lipids which may form complicated layers within the stratum corneum thus forming a "water barrier" which prevents water loss from the skin. It has been discovered that formulations may be prepared composed of components of the skin's natural water barrier forming lipid complex and that when these formulations are used by themselves or when they are incorporated into creams, ointments, gels and lotions, the resulting products provide unsurpassed protection against and treatment for dry skin conditions.
In preparing the formulations disclosed herein, combinations of components from three separate classes of lipids occurring naturally in the stratum corneum can be utilized: (1) fatty acids, in either the free acid form or as triglycerides; (2) sterols and sterol esters; and (3) phospholipids and glycolipids.